FlyingChihuahua
Hero
1) Remove Agonizing Blast. Any other feature that gives +stat mod to cantrips (like Dragon Sorcerers) is modified to not do that, 1st level spells +only. Remove Booming Blade/Greenflame Blade. Cantrip damage scales with class level, not character level. Casters should fall back on at-will damage as a last resort. If the Elf Wizard does better damage with their long bow than with Fire Bolt, that's awesome.
2) Remove any feat that favors using one weapon type or style over another. (Polearm Master, Sharpshooter, Crossbow Expert, Great Weapon Master, Dual Wielder.) Martials should be versatile. If you want a fighter that's a master of one weapon, roleplay him that way. (Weapon Specialization has been problematic since BECMI).
3) Give fighters, paladins, and rangers access to every fighting style at level 1 or 2, respectively. Makes them versatile, and gives them a baseline superiority in weapon attacks to non-warriors. Give Barbarians Dueling, Dual Wielding, and Great Weapon Fighter fighting styles at level 2. Give champion fighters something at level 10 to compensate. Everyone will want to dip Fighter 1, but considering Fighters are the Honda Civic of D&D, I don't see that as a problem.
There. Damage scaled down to a better baseline, and martials exceed casters easily in baseline capability. Make some new feats and spells, and maybe some new magic items, to balance to taste.
That sounds great.
In fact, why spellcasters get special toys that the martials don't? Martials should have equal access to spell-like abilities the equate to anything that a spell can do. In fact, let's go even farther for balance. Everything now does the same amount of damage. Perfectly balanced, as all things should be.